Previously in cross-flow cooling towers, where there was a need to balance the two halves of such a tower, or to balance separate units, this was accomplished by placing a butterfly valve in the hot water inlet pipe. However, this system suffered from the disadvantage of adversely affecting the water flow distribution downstream of the valve such that the water flow was non-uniform over the predistribution pan thereby leading to non-uniform distribution of water to the fill chamber and subsequent reduced thermal performance. In addition, such a system added significantly to the height of the overall system thus necessitating the separate shipment of the valve parts and field assembly when the oversized unit could not be shipped.